Iv done research on this for quite some time now (been sidetracked a few times by topics outside the one iv been searching for) and found numerous threads pertaining to the milky foam found on the dipstick when checking the oil. Now im one of those candidates who has this problem. I know its due to the temp changes getting colder and quite frankly, it may be the cause of my low fuel consumption although that idea may be far fetched.
Now iv done a search and found that a catch can should solve this issue (the foaming on the dipstick), however, i also found that a breather will solve the problem. So that being the case, Iv been on e-bay and found many different kinds of catch cans ranging from 15 dollars to over 100 dollars. Then iv seen breathers that range roughly around 5-10 dollars. Iv also seen catch cans with breathers built into them that cost about 50 dollars.
In order for me to iliminate the foam and prevent oil build-up in the intake, would it be wise to get the catch can with the breather built in? Also, (assuming the breather is not necessary) is there a significant difference in performance via the more expensive catch cans or will the cheaper ones work just as effectively?
Any information on this topic would be helpful. Thanx.

You don't need an oil catch can if your car is a 2006 or newer.

2004 GT 6-speed

The hose from the Oil Filler goes directly into the Air Intake manifold for the 2004's. I would buy an oil catch can for that although there's alot of debate on it.
So, if I were in you shoes, I'd buy an oil catch can.

man learn to spell i kept reading your "iv" as roman numeral 4.... it really interrupts the sentences

the catch can will not eliminate the milky buildup on the dipstick, but will eliinate the oil build-up in the intake.

hmm. i have an 04, and i get the foamy stuff. but its 20 degrees out, and i dont have stuff in my intake (knock on wood) i just deal with it

If you buy the cheap oil catch can (like I did) make sure you seal up the fittings before you install it.

07 owner here

For the 06/07's I was thinking about one anyways. The hose that goes from the oil filler neck to the two primary intake runners is "moist" with oil. I really dont like the idea of oil coating the inside of my intake. So some way to remove the oil before it gets there seems like a good thing to do.

I dont know all the hose routing for the 06/07's. Is there an actual PCV valve present like on most piston engines? This would help prevent oil from reaching the intake

Dont mean to hijack this thread. Just wanted some input. Thanks

the foam doesnt hurt your car

The milky foam doesn't hurt the car and a catch can doesn't have anything to do with fixing it. Check finishlineperformance.com RX-8 bulletings on the Milky substance on dipstick TSB. The TSB shows a very detailed fix for the foam but, again it does not affect the car as this is only due to moisture and the colder tube where the dipstick is located, just can be a pain to read your oil level as you have to keep dipping and wiping the dipstick. In the engine itself the heat evaporates any moisture. The catch can keeps oil from getting into the intake at the filter (from the oil vent lines) two separate issues. For what it is worth, I have an 04 with 76K miles and have done neither the TSB or the catch can.

07 owner here

For the 06/07's I was thinking about one anyways. The hose that goes from the oil filler neck to the two primary intake runners is "moist" with oil. I really dont like the idea of oil coating the inside of my intake. So some way to remove the oil before it gets there seems like a good thing to do.

I dont know all the hose routing for the 06/07's. Is there an actual PCV valve present like on most piston engines? This would help prevent oil from reaching the intake

Dont mean to hijack this thread. Just wanted some input. Thanks


No PCV valve so far as I know (and I don't know much), but on the 07's the hose outputs MUCH further down the intake manifold then on 04's, which dumped oil into the manifold just behind the intake box :banghead: I assume this was done to prevent the extra intake port from getting gummed up with oil and unable to roll open. I'm pretty sure it keeps the rest of the intake a lot cleaner too.